Fan blade structure

ABSTRACT

A fan blade structure includes a case, a rotor and a fan blade unit. The case has a top portion and a sidewall portion connected to an outer periphery of the top portion to thereby define a receiving space therein. The rotor is mounted in the receiving space to contact with an inner wall surface of the sidewall portion in a tight-fit relation. The fan blade unit is formed by stamping a metal material, and includes an annular top face bearing on the top portion of the case, and a plurality of blades equally spaced along the annular top face. The annular top face defines a large-area central opening, which effectively reduces an overall weight of the fan blade unit and thereby lowers the load of the rotor and allows a fan motor in operation to reach its high limit of rotary speed and enable an upgraded fan rotating speed.

FIELD OF THE INVENTION

The present invention relates to a fan blade structure, and more particularly to a fan blade structure having a fan blade unit with an annular top face defining a large-area central opening to thereby effectively reduce an overall weight of the fan blade unit, lower the load of a rotor of the fan blade structure, and allow a fan motor in operation to reach its high limit of rotary speed to enable upgraded fan rotating speed.

BACKGROUND OF THE INVENTION

Following the quick development in the electronic industrial field during recent years, electronic devices have rapidly enhanced performance, and chip sets inside the electronic devices are increased in number and have constantly increased computing and processing speed. As a result, the heat produced by the chip sets during operation also increases. The produced heat must be timely removed from the electronic devices and the chip sets to avoid adverse influence on the electronic devices' performance and operating speed thereof. The accumulated heat in the electronic devices would even burn out the electronic devices and the chip sets. Therefore, it has become an important issue to dissipate the heat produced by the electronic devices during the operation thereof. Currently, a common way to dissipate the heat is to use a cooling fan as a heat dissipation device.

The currently available cooling fans can be generally divided into plastic fan and metal fan according to the material used to manufacture the cooling fans. In practical use, the plastic fan has lower durability compared to the metal fan. For example, the plastic fan has blades that are easily subject to damage due to impact or compression. Therefore, fan manufacturers have positively engaged in researching and developing the metal fan.

Please refer to FIGS. 1A and 1B that are exploded and assembled perspective views, respectively, of a conventional fan structure. The conventional fan structure is made of a metal material and includes a hub 10 and a fan blade unit 12. The fan blade unit 12 includes a plurality of blades 121 and a connecting member 122. The whole fan blade unit 12 is formed by stamping a metal material. The blades 121 are spaced along and outward extended from an outer periphery of the connecting member 122. The fan blade unit 12 is fitted on a top of the hub 10 with the connecting member 122 and a proximal end of the blades 121 bearing on and welded to a top face and a peripheral wall, respectively, of the hub 10 to complete the fan structure. The hub 10 is then associated with a rotor (not shown), so that the fan structure is brought by the rotor to rotate.

While the metal fan structure overcomes the problems of poor durability and easily subjecting to damage as found in the plastic fan, the fan blade unit 12 completely made of a metal material by stamping and welded to the hub 10 has an excessively high weight to increase the load of the rotor. The fan motor for driving the rotor to rotate also fails to reach its high limit of rotary speed due to the large load of the rotor, and accordingly, the airflow output by the fan is adversely reduced.

In brief, the conventional fan structure has the following disadvantages: (1) the blades are extremely heavy; (2) the rotor has increased load; (3) the fan has reduced rotating speed; and (4) the fan motor fails to reach its high limit of rotary speed.

It is therefore tried by the inventor to develop an improved fan blade structure to lower the load of the rotor and increase the rotating speed of the fan.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide a fan blade structure that effectively reduces the load of a rotor thereof.

To achieve the above and other objects, the fan blade structure according to a preferred embodiment of the present invention includes a case, a rotor and a fan blade unit. The case has a top portion and a sidewall portion connected to an outer periphery of the top portion to thereby define a receiving space therein. The rotor is mounted in the receiving space to contact with an inner wall surface of the sidewall portion in a tight-fit relation. The fan blade unit is formed by stamping a metal material for mounting on the case, and includes an annular top face bearing on the top portion of the case, and a plurality of blades equally spaced along the annular top face. The annular top face defines a large-area central opening, from which a large part of the top portion of the case is exposed. The blades each are connected to the annular top face via an extension section extended from an outer periphery of the annular top face, and the extension sections are welded to the sidewall portion of the case. The central opening effectively reduces an overall weight of the fan blade unit and thereby lowers the load of the rotor and allows a fan motor in operation to reach its high limit of rotary speed to upgrade the fan rotating speed.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein

FIG. 1A is an exploded perspective view of a conventional fan structure;

FIG. 1B is an assembled view of FIG. 1;

FIG. 2 is an exploded perspective view of a fan blade structure according to a preferred embodiment of the present invention; and

FIG. 3 is an assembled view of FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please refer to FIGS. 2 and 3 that are exploded and assembled perspective views, respectively, of a fan blade structure according to a preferred embodiment of the present invention. As shown, the fan blade structure includes a case 2, a rotor 3, and a fan blade unit 4. The case 2 has a top portion 21 and a sidewall portion 22. The sidewall portion 22 is connected at an end to an outer periphery of the top portion 21, so that a receiving space 23 is defined between the top portion 21 and the sidewall portion 22. The rotor 3 is mounted in the receiving space 23 to contact with an inner wall surface of the sidewall portion 23 in a tight-fit relation. A shaft seat 31 is fixedly mounted to a center of the case 2 for a shaft 32 to fixedly insert therein.

The fan blade unit 4 is formed by stamping a metal material, such as iron, aluminum, copper and other metal alloys. The fan blade unit 4 includes an annular top face 41 for bearing on the top portion 21 of the case 2. Since the annular top face 41 internally defines a large-area central opening 42, only a small contact surface is existed between the annular top face 41 and the outer periphery of the top portion 21. That is, a large area of the top portion 21 is exposed from the central opening 42 of the annular top face 41. The fan blade unit 4 further includes a plurality of spaced extension sections 43 extended from an outer periphery of the annular top face 41 for bearing on the sidewall portion 22. Each of the extension sections 43 has a proximal end integrally connected to the outer periphery of the annular top face 41 and a distal end connected to a blade 44. The blade 44 has a front edge 441, a rear edge 442, and an air-guiding face 443. The air-guiding face 443 is located between the front edge 441 and the rear edge 442, and has one side connected to the extension section 43. The blades 44 are in an angular position relative to the extension sections 43 and are equally spaced along the annular top face 41, such that the front edge 441 of any of the blades 44 is spaced from and located higher than the rear edge 442 of an adjacent preceding blade 44 by a fixed distance.

The fan blade unit 4 is fixedly held to the case 2 by welding the annular top face 41 and the extension sections 43 to the top portion 21 and the sidewall portion 22, respectively, to complete the assembling of the fan blade structure of the present invention. With the large-area central opening 42 of the annular top face 41 of the fan blade unit 4, an overall weight of the fan blade unit 4 is effectively reduced to thereby lower the load of the rotor 3 and allow a fan motor in operation to reach a high limit of rotary speed thereof to enable an increased fan rotating speed.

In brief, the fan blade structure according to the present invention provides the following advantages: (1) effectively reducing the overall weight of the fan blade unit; (2) lowering the load of the rotor; (3) increasing the fan rotating speed; and (4) allowing the fan motor in operation to reach the high limit of rotary speed thereof.

The present invention has been described with a preferred embodiment thereof and it is understood that many changes and modifications in the described embodiment can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims. 

1. A fan blade structure, comprising: a case having a top portion and a sidewall portion, the sidewall portion being connected at one end to an outer periphery of the top portion to thereby define a receiving space between the top portion and the sidewall portion; a rotor being mounted in the receiving space in the case to contact with an inner wall surface of the sidewall portion in a tight-fit relation; and a fan blade unit including an annular top face for bearing on the top portion of the case, and a plurality of blades extended from an outer periphery of the annular top face; and the annular top face defining a large-area central opening, from which a large part of the top portion of the case is exposed.
 2. The fan blade structure as claimed in claim 1, wherein the fan blade unit is fixedly held to the case by welding the annular top face to the top portion of the case.
 3. The fan blade structure as claimed in claim 1, wherein the fan blade unit is formed by stamping to directly form the central opening on the annular top face while stamping, so as to effectively reduce an overall weight of the fan blade unit.
 4. The fan blade structure as claimed in claim 3, wherein the fan blade unit is formed by stamping a metal material.
 5. The fan blade structure as claimed in claim 1, wherein the fan blade unit further includes at least one extension section; the extension section having a proximal end integrally connected to the outer periphery of the annular top face and a distal end integrally connected to one side of the blades.
 6. The fan blade structure as claimed in claim 5, wherein each of the blades has a front edge, a rear edge, and an air-guiding face; and the air-guiding face being located between the front edge and the rear edge with one side connected to the extension section.
 7. The fan blade structure as claimed in claim 6, wherein the front edge of any of the blades is spaced from and located higher than the rear edge of an adjacent preceding blade by a fixed distance. 